UNIX for Advanced & Expert Users

Hello, colleges!
I need to synchronize time on several thousands device (UTM-1 Edge Appliances - All inclusive, all secure, all branch offices.) which don`t understand summer time at all. But in my country summer time are used.
I plan to sync it with NTP server with modificated time: plus one hour or normal depending of season. But how to make this modificated time on NTP Windows or Unix server?

I read NTP docs on its inventor page ntpd - Network Time Protocol (NTP) daemon and plan to use "tinker step" parameter. Is it true?
Does somebody solve this problem ever before?

tinker will not fix your problem. You most likely need to modify the timezore rules on the affected local systems.

An NTP server communicates time in terms of Greenwich Mean Time (GMT), otherwise referred to as Universal Time Coordinated (UTC). When a local system synchronizes with an NTP server, it is obtaining UTC time information. By convention, UTC is not subject to any DST rules. The local system is always responsible for converting UTC into the appropriate local time, including DST, and must be updated with new DST rules anytime they change.

I would ask that the vendor give you a patch.
it's just a timezone file.

they should support the product......